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POCALayer transform is wrong after going back to the screen
 

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  1. POCALayer transform is wrong after going back to the screen
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    <p>I have a UIView to which I'm applying a CAAnimation. <em>animation</em> is an instance of a class that inherits from CAKeyframeAnimation, which keypath is @"transform.scale".</p> <pre><code>[[myView layer] addAnimation:animation forKey:@"animation key"]; [[myView layer] setValue:[NSNumber numberWithBool:finalScale] forKey:@"transform.scale"]; </code></pre> <p>As usual, besides adding the animation I'm setting the value so that when it's over, it doesn't go back to the original state.</p> <p>This all works nicely. However, if I exit this controller and then go back, somehow that layer has this transform applied twice, so it looks 4 times smaller, even though the current value is <em>finalScale</em>.</p> <p>I've tried saving the current transform on viewWillDisappear and apply that again on viewWillAppear. Also tried this on viewWillAppear:</p> <pre><code>[myView.layer setTransform:CATransform3DIdentity]; </code></pre> <p>But none of those worked. It looks like there is some other matrix calculation being made under the hood, or am I missing something?</p> <p>EDIT: This is how I'm creating the animation:</p> <pre><code>double startValue = [[view.layer.presentationLayer valueForKeyPath:@"transform.scale"] doubleValue]; ExponentialAnimation *animation = [ExponentialAnimation animationWithKeyPath:@"transform.scale" startValue:startValue endValue:endValue duration:kDuration]; [view.layer removeAnimationForKey:@"scale"]; [view.layer addAnimation:animation forKey:@"scale"]; [view.layer setValue:[NSNumber numberWithFloat:endValue] forKeyPath:@"transform.scale"]; </code></pre> <p>ExponentialAnimation looks like this:</p> <pre><code>@interface ExponentialAnimation : CAKeyframeAnimation { double _startValue; double _endValue; NSUInteger _steps; } @implementation ExponentialAnimation @synthesize startValue=_startValue, endValue=_endValue; + (id)animationWithKeyPath:(NSString *)keyPath startValue:(double)startValue endValue:(double)endValue duration:(CGFloat)duration { return [[[self alloc] initWithKeyPath:keyPath startValue:startValue endValue:endValue duration:duration] autorelease]; } - (id)initWithKeyPath:(NSString *)keyPath startValue:(double)start endValue:(double)end duration:(CGFloat)duration { if ((self = [super init])) { self.keyPath = keyPath; self.duration = duration; _startValue = start; _endValue = end; _steps = [self numberOfStepsForDuration:duration withFPS:kAnimationFPS]; [self calculateKeyFrames]; } return self; } </code></pre> <p>calculateSteps just creates an array of values for every keyframe and adds it like:</p> <pre><code>[self setValues:values]; </code></pre> <p>When the viewController disappears, <em>view</em> has scale set to 0.4 (<em>endValue</em> in the animation). When I go back, getting the value of [view.layer valueForKeyPath:@"transform.scale"] gives 0.4, but what you really see is something like 0.4 * 0.4.</p>
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    1. USNachoSoto
    1. USNachoSoto
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      1. POCALayer transform is wrong after going back to the screen
      1. USNachoSoto
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      1. POCALayer transform is wrong after going back to the screen
      1. USFiroze Lafeer
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    1. COTry adding this after the snippet you posted in viewWillAppear: `[self setNeedsLayout]; [self layoutIfNeeded];`
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      1. POCALayer transform is wrong after going back to the screen
      1. UStitaniumdecoy
    2. CO@titaniumdecoy no luck...
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      1. USNachoSoto
    3. COPosting more code might help
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      1. POCALayer transform is wrong after going back to the screen
      1. UStitaniumdecoy
 

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